1. Field of the Invention
The present invention relates generally to membranes for separating oil from an oil-water mixture, and particularly to a nanostructured membrane including a zinc oxide nanorod coating for separating oil from an oil-water mixture.
2. Description of the Related Art
Oil-water separation has been a global challenge owing to heavy discharge of oily wastewater and frequent oil spill accidents. Currently, porous materials like sponges, meshes, and other membranes formed from flexible or rigid materials are utilized as oil-water separators. However, these traditional membranes typically tend to adsorb water along with oil due to some surface hydrophilicity. Various approaches have been put forward to overcome this challenge by modifying the surface texture and surface chemistry of such structures or membranes. Recent technologies to fabricate oil-water separating membranes involve coating membrane surfaces to render the surfaces hydrophobic. Typical coating techniques include, for example, chemical vapor deposition, layer by layer deposition, electro-spinning and chemical deposition method.
Conventional oil-water separating membranes cannot separate all of the oil from an oil-water mixture (about 50 PPM oil remains after skimming). Accordingly, oil-contaminated water remains even after conventional separation operations are completed. Further, these conventional techniques have other disadvantages, including high cost and sophisticated process requirements needing skilled manpower. Therefore it would be desirable to produce a simple and cost effective process for large scale production of modified membranes for oil-water separation, which are particularly useful for the oil and gas industry.
Thus, a nanostructured membrane capable of separating oil from water solving the aforementioned problems is desired.